Joe Sellers, Dr. Scott Flynn - Fescue Toxicosis in Beef Cattle: Understanding and Managing the...
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Transcript of Joe Sellers, Dr. Scott Flynn - Fescue Toxicosis in Beef Cattle: Understanding and Managing the...
Fescue Toxicosis
Joe Sellers(Thanks to Craig Roberts and Steve Barnhart
for material)
How is fescue a problem in
Iowa?• It is moving further north
• It is colder here than in other fescue belt
states
• We have lost a lot of improved non-fescue
pastures (35% less pasture than 2002)
• Increasing spring growth with N makes it
worse
Questions I get
• Does clipping stop the problem?
• How long does it effect the cattle after they are
removed from fescue?
• Are some cattle immune to the effects?
• Do some mineral additives eliminate the
problem?
• How do I identify it?
Tall Fescue Endophyte Life Cycle
Active endophytefungus infects newgrass seedling
Fungus entersthe rapidly elongatingstem tissue
Fungus Myceliuminvades thedeveloping seed
Grass Vegetative Stage:Most Active Fungus Growth in Leaf Sheaths
Fescue BMPs
• Keep vegetative
• Introduce legumes
• Careful with N fertilization
• Fescue toxicosis is a health disorder, not nutritional, but --
• You must meet cow mineral requirements
• Dilute with other feeds, forages
• Renovate with spray/smother/spray
Fescue BMPs
• Good for calving pastures
• Hay will have 50% alkaloid level compared to grazed
• If stockpile, do it from August 1
• Source genetics from herds with fescue
• Mineral additives – some data finds response, but mixed results
Vasoconstriction (narrowing of blood vessels)
Fescue foot
Poor thermoregulation
Low feed intake
Low rate of gain
Dystocia (birthing problems) and poor reproduction
Aglactia (poor milk production)
Fescue Toxicosis
© George Garner
1400
1000
600
Duckett et al., 2001
Problems exist even if native
cattle and no visible signs• Gain and reproductive losses
• Seed heads and stems are worse, but
alkaloids are in all of the plant
• Year to year and seasonal differences
1999 2000
------- lb/d -------
Toxic endopyte 0.73 0.50
Endophyte-free 1.26 1.56
Novel endophyte 1.30 1.54
Steer gains on three types of fescue
0
200
400
600
800
1,000
Ap
ril
May
Jun
e
July
Au
gust
Sep
tem
be
r
Oct
ob
er
Ergo
valin
e (
µg
kg-1
DM
)
Georgia Missouri South Carolina
Rogers et al., 2011
Alkaloid Management!
In endophyte (replant)
In plant (fertilizers, seasonal, anatomical)
In pasture (dilution, rotations)
In diet (ammoniation, supplementation)
Spray Smother Spray Renovation Experiment with small acreage
Plan for fall plant if possible (Sept. 1 for mid-MO)
If replacing E+ KY31, may clip seed heads in spring
Also if replacing E+ KY31, “spray-smother-spray”
Add legumes later (except for BFT)
15 lb/A drilled; 1/8” deep
Add N for “pop-up” (30 to 40 lb/A)
OldStand
SummerAnnual
NewStand
spray & plant
Spring Summer Fall
spray & plant
Yiel
d
grass only
with rotation
with supplement
with legumes
E+ E-
Dai
ly G
ain
(lb
/A)
Incremental Alleviation
Tall fescue Smooth bromegrass Orchardgrass Red clover White clover Birdsfoot trefoil
Dilute the Field
Nitrogen increases alkaloid concentration
High nitrogen associated with toxicosis
Nitrogen Fertilizer (lb/acre)
0 60 120
------- Ergovaline (ppb) -------
Leaf 258 306 485
Stem and Sheath 494 561 1,003
Seedhead 895 1,050 1,488
Rottinghaus et al., 1991
Careful Fertilization
?
Roberts et al, 2002
Roberts et al, 2009
Graze Stockpile Late Winter
© Rob Kallenbach
Kallenbach et al, 2003
Grazing stockpile
• Reduces Hay 2390/lbs per cow compared to dry lot (three year average)
• Stockpile from around August 1 for beef balance of yield and quality
• Graze cornstalks first, then stockpiled fescue (quality, less alkaloids in fescue)
Stockpiled legume/fescue
Pasture management
is important• www.iowabeefcenter.org
• Joe Sellers, 641-203-1270
• Welcome, Scott Flynn, Dow AgroSciences